The present invention relates to a torus type nuclear fusion apparatus which uses deuterium or tritium as fuel. The apparatus has a means on a first wall of a blanket capable of generating torus type plasma in a plasma confinement region enclosed by the first wall and evacuating helium gas formed by neutralizing helium ion, a product of fusion reaction.
This type nuclear fusion apparatus is well known and makes it necessary for a limiter to be arranged on the first wall, contacting and stabilizing the plasma, and for deuterium or tritium to be supplied as fuel while evacuating helium ions, a product of nuclear fusion reaction, so as to stably maintain the nuclear fusion reaction for a long time.
In order to discharge helium ions, it is necessary to introduce helium ions into a room pumped by a evacuating pump and to neutralize the helium ions there to transform them to helium gas. The most usual way employed is to use diverters to generate a magnetic field, but a large space is needed to accommodate diverter coils in this case and the design of coils for forming magnetic field is not easy, too. It was therefore attempted that helium ions were was evacuated through a suction room without using diverters. Helium ions must also be neutralized in this case and it is therefore preferable to use a solid limiter. Conventionally, the solid limiter was attached to the first wall of the blanket and served to stably maintain plasma and to neutralize helium ions. Since a large amount of heat was exerted on the limiter, however, a strongly cooling means was needed to keep the temperature of the limiter in a safety range, thus making the whole of the nuclear fusion apparatus bulky.